From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4441DC32767 for ; Fri, 3 Jan 2020 15:55:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2002E222C4 for ; Fri, 3 Jan 2020 15:55:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727884AbgACPzQ (ORCPT ); Fri, 3 Jan 2020 10:55:16 -0500 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:59624 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727539AbgACPzQ (ORCPT ); Fri, 3 Jan 2020 10:55:16 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R211e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07487;MF=wenyang@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0TmkFDOs_1578066907; Received: from localhost(mailfrom:wenyang@linux.alibaba.com fp:SMTPD_---0TmkFDOs_1578066907) by smtp.aliyun-inc.com(127.0.0.1); Fri, 03 Jan 2020 23:55:13 +0800 From: Wen Yang To: rjw@rjwysocki.net, Len Brown , Pavel Machek Cc: Wen Yang , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] kernel/power/snapshot.c: improve arithmetic divisions Date: Fri, 3 Jan 2020 23:54:58 +0800 Message-Id: <20200103155458.21707-1-wenyang@linux.alibaba.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org do_div() does a 64-by-32 division. Use div64_u64() instead of do_div() if the divisor is u64, to avoid truncation to 32-bit. This change also cleans up code a tad. Signed-off-by: Wen Yang Cc: "Rafael J. Wysocki" Cc: Len Brown Cc: Pavel Machek Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org --- kernel/power/snapshot.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c index 26b9168..8a6eaf7 100644 --- a/kernel/power/snapshot.c +++ b/kernel/power/snapshot.c @@ -1566,9 +1566,7 @@ static unsigned long preallocate_image_highmem(unsigned long nr_pages) */ static unsigned long __fraction(u64 x, u64 multiplier, u64 base) { - x *= multiplier; - do_div(x, base); - return (unsigned long)x; + return div64_u64(x * multiplier, base); } static unsigned long preallocate_highmem_fraction(unsigned long nr_pages, -- 1.8.3.1